ABU DHABI, United Arab Emirates — A Japanese supertanker damaged last month in the Strait of Hormuz was the target of a terrorist attack, according to a military source quoted Friday by the Emirates News Agency.

The state-owned agency reported that a UAE Coast Guard source said special investigators confirmed that homemade explosives were found in the dented starboard side of the supertanker's hull.

The statement came two days after a militant group linked to al-Qaida claimed responsibility for the incident that damaged the M. Star.

The tanker, which is owned by Mitsui O.S.K. Lines, left the Port of Fujairah Friday after repairs were completed.

It was hit while passing through international waters midnight on July 28.

Besides damaging the hull, the blast blew off a lifeboat and smashed windows and doors.

"Probably the tanker had encountered a terrorist attack from a boat loaded with explosives," the source said.

A U.S. Navy team last week examined the ship to determine the extent of damage, Lt. John Fage, the spokesperson for the Navy’s Bahrain-based Fifth Fleet, said at the time.

The incident initially sparked theories ranging from a freak wave to a collision with a U.S. nuclear submarine or a mine leftover from the Iran-Iraq War.

On Wednesday, a group calling itself the Abdullah Azzam Brigades posted a claim of responsibility for the attack and a photo of its alleged suicide bomber on a website used by Islamist militants.

The group's claim was met with some skepticism.

Mustafa Alani, a senior adviser at the Gulf Research Center in Dubai, told the National newspaper of Abu Dhabi that he believed a delay in investigations, plus the unclear cause of the damage, had prompted the group to claim responsibility.

Bordered by Iran, Oman and the United Arab Emirates, the narrow Strait of Hormuz handles 40 percent of the world's seaborne oil and is patrolled by U.S. and other warships. Al-Qaida has threatened to attack shipping there in the past.